In industries such as food, feed, agriculture, drug, animal drug, personal care, skin care, etc., the use of certain ingredients or extracts is difficult since their constituent materials have low or poor solubility in water, which leads to low stability, accessibility, availability, or bioavailability. Examples of such ingredients, synthetic compounds, or extracts can include phenolic compounds (e.g., flavonoids, curcuminoids), carotenoids and active pharmaceutical ingredients (APIs, e.g., drugs), as well as raw or purified extracts from herbs, microbes and animals.
One particular example of such ingredients or extracts includes phenolic compounds, such as quercetin and curcumin. Quercetin and curcumin are strong antioxidants and have anti-inflammatory, antiviral, and anti-cancer effects. In particular, curcumin is a potent anti-cancer drug that can be used clinically. However, their low solubility prohibits their use in food, nutraceutical, cosmetic, and medical formulations. To address this problem, a variety of techniques have been employed to improve the water-solubility of such low or non-soluble phenolic compounds. For example, it has been proposed to improve the solubility of curcumin using specific compounds (e.g., piperine), polymeric nanoparticle encapsulation, or surfactant micelles to disperse curcumin and improve its solubility. However, these methods are expensive and/or have limited capability to solubilize phenolic compounds. In addition, some of these strategies are simply ineffective.
Poor water solubility of some active pharmaceutical ingredients (APIs), such as a number of drugs is one of the major problems in drug formulation and drug absorption. Systems to improve the water solubility of these drugs are essential for their bioavailability. For example, application of paclitaxel in cancer therapy has been limited by its low water solubility, and current practice of dissolving paclitaxel usually leads to short-term physical stability with quick precipitation of drug molecules. To enhance paclitaxel solubility and physical stability, hydrotropes have been used to complex with drug molecules. To be effective, however, the concentration of hydrotropes needs to be very high, which may lead to difficulties in formulation and administration.
Another example is ibuprofen. Ibuprofen is a nonsteroidal anti-inflammatory drug (NSAID), and a core medicine in the WHO Model List of Essential Medicines. It is broadly used to relieve symptoms of arthritis and fever and as an analgesic where there is an inflammatory component and dysmenorrhea. Ibuprofen belongs to Biopharmaceutics Classification System (BCS) class II, for which the rate of drug dissolution or drug solubility is the rate-limiting step in the absorption.
Another example is Griseofulvin. Griseofulvin is a widely used antifungal drug in the treatment of mycotic diseases of skin, hair and nails. Griseofulvin is poorly soluble in water and has been used as a standard in the research to increase drug bioavailability.
Similar issues persist in industries related to the extraction and formulation of medicinal, nutritional, or functional materials from plant, microbial, or animal organisms, such as herbal extracts, Chinese medicine, and colorants. In such industries, there are a number of extraction processes, including: (1) aqueous extraction; (2) solvent-based extraction and (3) supercritical fluid extraction. In many circumstances, the solute compound (or materials) has low water solubility, which makes it difficult to formulate as a product. Additionally, in industries related to feed, animal drugs, personal care, cosmetics, paints, pesticides, herbicides, or other food and non-food areas, the low solubility of certain materials in products is the source of numerous difficulties in formulation, processing and/or the function of such products.